package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.dto.ScrollResult;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Blog;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.BlogMapper;
import com.hmdp.service.IBlogService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IFollowService;
import com.hmdp.service.IUserService;
import com.hmdp.utils.SystemConstants;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ZSetOperations;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

import static com.hmdp.utils.RedisConstants.BLOG_LIKED_KEY;
import static com.hmdp.utils.RedisConstants.FEED_KEY;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class BlogServiceImpl extends ServiceImpl<BlogMapper, Blog> implements IBlogService {
    @Resource
    private IUserService userService;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    @Resource
    private IFollowService followService;

    @Override
    public Result queryBlogById (Long id) {
        Blog blog = getById(id);
        if (blog == null) {
            return Result.fail("笔记不存在");
        }
        queryBlogUser (blog);
        isBlogLiked(blog);
        return Result.ok(blog);
    }

    private void isBlogLiked (Blog blog) {
        UserDTO user = UserHolder.getUser();
        if (user == null) {
            return;
        }
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + blog.getId ();
        Double score = stringRedisTemplate.opsForZSet ().score (key, userId.toString ());
        blog.setIsLike (score != null);
    }

    @Override
    public Result queryHotBlog (Integer current) {
        // 根据用户查询
        Page<Blog> page = query()
                .orderByDesc("liked")
                .page(new Page<>(current, SystemConstants.MAX_PAGE_SIZE));
        // 获取当前页数据
        List<Blog> records = page.getRecords();
        // 查询用户
        records.forEach(blog ->{
            this.queryBlogUser (blog);
            this.isBlogLiked(blog);
        });
        return Result.ok(records);
    }

    private void queryBlogUser (Blog blog) {
        Long userId = blog.getUserId();
        User user = userService.getById(userId);
        blog.setName(user.getNickName());
        blog.setIcon(user.getIcon());
    }

    @Override
    public Result likeBlog (Long id) {
        Long userId = UserHolder.getUser().getId();
        String key = BLOG_LIKED_KEY + id;
        Double score = stringRedisTemplate.opsForZSet ().score (key, userId.toString ());
        if (score == null){
            boolean isSuccess = update ().setSql ("liked = liked + 1").eq ("id", id).update ();
            if(isSuccess){
                stringRedisTemplate.opsForZSet ().add (key, userId.toString (),System.currentTimeMillis ());
            }
        }else{
            boolean isSuccess = update ().setSql ("liked = liked - 1").eq ("id", id).update ();
            if(isSuccess){
                stringRedisTemplate.opsForZSet ().remove (key,userId.toString ());
            }
        }
        return Result.ok ();
    }

    @Override
    public Result queryBlogLikes (Long id) {
        String key = BLOG_LIKED_KEY + id;
        Set<String> top5 = stringRedisTemplate.opsForZSet().range(key, 0, 4);
        if (top5 == null || top5.isEmpty ()){
            return Result.ok (Collections.emptyList ());
        }
        List<Long> ids = top5.stream ().map (Long::valueOf).collect (Collectors.toList ());
        String idStr = StrUtil.join (",", ids);
        List<UserDTO> userDTOS = userService.query ()
                .in ("id", ids).last ("ORDER BY FIELD (id," + idStr + ")").list ()
                .stream ()
                .map (user -> BeanUtil.copyProperties (user, UserDTO.class))
                .collect (Collectors.toList ());

        return Result.ok (userDTOS);
    }

    @Override
    public Result saveBlog (Blog blog) {
        UserDTO user = UserHolder.getUser();
        blog.setUserId(user.getId());
        boolean isSuccess = save (blog);
        if (!isSuccess){
            return Result.fail ("新增笔记失败");
        }
        List<Follow> follows = followService.query ().eq ("follow_user_id", user.getId ()).list ();
        for (Follow follow : follows) {
            Long userId = follow.getUserId ();
            String key = FEED_KEY + userId;
            stringRedisTemplate.opsForZSet ().add(key, blog.getId ().toString (),System.currentTimeMillis ());
        }
        return Result.ok (blog.getId ());
    }

    @Override
    public Result queryBlogOfFollow (Long max, Integer offset) {
        UserDTO user = UserHolder.getUser();
        String key = FEED_KEY + user.getId ();
        Set<ZSetOperations.TypedTuple<String>> typedTuples = stringRedisTemplate.opsForZSet ()
                .reverseRangeByScoreWithScores (key, 0, max, offset, 2);
        if (typedTuples == null || typedTuples.isEmpty ()){
            return Result.ok ();
        }
        long minTime = 0;
        int os =1;
        List<Long> ids = new ArrayList<> (typedTuples.size ());
        for (ZSetOperations.TypedTuple<String> tuple : typedTuples){
            String blogId = tuple.getValue ();
            ids.add (Long.valueOf (blogId));
            long time = tuple.getScore ().longValue ();
            if (minTime == time){
                os++;
            }else{
                minTime = time;
                os = 1;
            }
        }
        String idStr = StrUtil.join (",", ids);
        List<Blog> blogs = query().in ("id", ids).last ("ORDER BY FIELD (id," + idStr + ")").list ();
        blogs.forEach (blog ->{
            this.queryBlogUser (blog);
            this.isBlogLiked(blog);
        });
        ScrollResult scrollResult = new ScrollResult ();
        scrollResult.setList (blogs);
        scrollResult.setOffset (os);
        scrollResult.setMinTime (minTime);
        return Result.ok (scrollResult);
    }
}
